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Diffstat (limited to 'binutils-2.25/elfcpp/elfcpp_swap.h')
| -rw-r--r-- | binutils-2.25/elfcpp/elfcpp_swap.h | 500 |
1 files changed, 500 insertions, 0 deletions
diff --git a/binutils-2.25/elfcpp/elfcpp_swap.h b/binutils-2.25/elfcpp/elfcpp_swap.h new file mode 100644 index 00000000..833da5da --- /dev/null +++ b/binutils-2.25/elfcpp/elfcpp_swap.h @@ -0,0 +1,500 @@ +// elfcpp_swap.h -- Handle swapping for elfcpp -*- C++ -*- + +// Copyright 2006, 2007, 2008, 2009, 2012 Free Software Foundation, Inc. +// Written by Ian Lance Taylor <iant@google.com>. + +// This file is part of elfcpp. + +// This program is free software; you can redistribute it and/or +// modify it under the terms of the GNU Library General Public License +// as published by the Free Software Foundation; either version 2, or +// (at your option) any later version. + +// In addition to the permissions in the GNU Library General Public +// License, the Free Software Foundation gives you unlimited +// permission to link the compiled version of this file into +// combinations with other programs, and to distribute those +// combinations without any restriction coming from the use of this +// file. (The Library Public License restrictions do apply in other +// respects; for example, they cover modification of the file, and +/// distribution when not linked into a combined executable.) + +// This program is distributed in the hope that it will be useful, but +// WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// Library General Public License for more details. + +// You should have received a copy of the GNU Library General Public +// License along with this program; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA +// 02110-1301, USA. + +// This header file defines basic template classes to efficiently swap +// numbers between host form and target form. When the host and +// target have the same endianness, these turn into no-ops. + +#ifndef ELFCPP_SWAP_H +#define ELFCPP_SWAP_H + +#include <stdint.h> + +// We need an autoconf-generated config.h file for endianness and +// swapping. We check two macros: WORDS_BIGENDIAN and +// HAVE_BYTESWAP_H. + +#include "config.h" + +#ifdef HAVE_BYTESWAP_H +#include <byteswap.h> +#else +// Provide our own versions of the byteswap functions. +inline uint16_t +bswap_16(uint16_t v) +{ + return ((v >> 8) & 0xff) | ((v & 0xff) << 8); +} + +inline uint32_t +bswap_32(uint32_t v) +{ + return ( ((v & 0xff000000) >> 24) + | ((v & 0x00ff0000) >> 8) + | ((v & 0x0000ff00) << 8) + | ((v & 0x000000ff) << 24)); +} + +inline uint64_t +bswap_64(uint64_t v) +{ + return ( ((v & 0xff00000000000000ULL) >> 56) + | ((v & 0x00ff000000000000ULL) >> 40) + | ((v & 0x0000ff0000000000ULL) >> 24) + | ((v & 0x000000ff00000000ULL) >> 8) + | ((v & 0x00000000ff000000ULL) << 8) + | ((v & 0x0000000000ff0000ULL) << 24) + | ((v & 0x000000000000ff00ULL) << 40) + | ((v & 0x00000000000000ffULL) << 56)); +} +#endif // !defined(HAVE_BYTESWAP_H) + +// gcc 4.3 and later provides __builtin_bswap32 and __builtin_bswap64. + +#if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) +#undef bswap_32 +#define bswap_32 __builtin_bswap32 +#undef bswap_64 +#define bswap_64 __builtin_bswap64 +#endif + +namespace elfcpp +{ + +// Endian simply indicates whether the host is big endian or not. + +struct Endian +{ + public: + // Used for template specializations. + static const bool host_big_endian = +#ifdef WORDS_BIGENDIAN + true +#else + false +#endif + ; +}; + +// Valtype_base is a template based on size (8, 16, 32, 64) which +// defines the type Valtype as the unsigned integer, and +// Signed_valtype as the signed integer, of the specified size. + +template<int size> +struct Valtype_base; + +template<> +struct Valtype_base<8> +{ + typedef uint8_t Valtype; + typedef int8_t Signed_valtype; +}; + +template<> +struct Valtype_base<16> +{ + typedef uint16_t Valtype; + typedef int16_t Signed_valtype; +}; + +template<> +struct Valtype_base<32> +{ + typedef uint32_t Valtype; + typedef int32_t Signed_valtype; +}; + +template<> +struct Valtype_base<64> +{ + typedef uint64_t Valtype; + typedef int64_t Signed_valtype; +}; + +// Convert_endian is a template based on size and on whether the host +// and target have the same endianness. It defines the type Valtype +// as Valtype_base does, and also defines a function convert_host +// which takes an argument of type Valtype and returns the same value, +// but swapped if the host and target have different endianness. + +template<int size, bool same_endian> +struct Convert_endian; + +template<int size> +struct Convert_endian<size, true> +{ + typedef typename Valtype_base<size>::Valtype Valtype; + + static inline Valtype + convert_host(Valtype v) + { return v; } +}; + +template<> +struct Convert_endian<8, false> +{ + typedef Valtype_base<8>::Valtype Valtype; + + static inline Valtype + convert_host(Valtype v) + { return v; } +}; + +template<> +struct Convert_endian<16, false> +{ + typedef Valtype_base<16>::Valtype Valtype; + + static inline Valtype + convert_host(Valtype v) + { return bswap_16(v); } +}; + +template<> +struct Convert_endian<32, false> +{ + typedef Valtype_base<32>::Valtype Valtype; + + static inline Valtype + convert_host(Valtype v) + { return bswap_32(v); } +}; + +template<> +struct Convert_endian<64, false> +{ + typedef Valtype_base<64>::Valtype Valtype; + + static inline Valtype + convert_host(Valtype v) + { return bswap_64(v); } +}; + +// Convert is a template based on size and on whether the target is +// big endian. It defines Valtype and convert_host like +// Convert_endian. That is, it is just like Convert_endian except in +// the meaning of the second template parameter. + +template<int size, bool big_endian> +struct Convert +{ + typedef typename Valtype_base<size>::Valtype Valtype; + + static inline Valtype + convert_host(Valtype v) + { + return Convert_endian<size, big_endian == Endian::host_big_endian> + ::convert_host(v); + } +}; + +// Swap is a template based on size and on whether the target is big +// endian. It defines the type Valtype and the functions readval and +// writeval. The functions read and write values of the appropriate +// size out of buffers, swapping them if necessary. readval and +// writeval are overloaded to take pointers to the appropriate type or +// pointers to unsigned char. + +template<int size, bool big_endian> +struct Swap +{ + typedef typename Valtype_base<size>::Valtype Valtype; + + static inline Valtype + readval(const Valtype* wv) + { return Convert<size, big_endian>::convert_host(*wv); } + + static inline void + writeval(Valtype* wv, Valtype v) + { *wv = Convert<size, big_endian>::convert_host(v); } + + static inline Valtype + readval(const unsigned char* wv) + { return readval(reinterpret_cast<const Valtype*>(wv)); } + + static inline void + writeval(unsigned char* wv, Valtype v) + { writeval(reinterpret_cast<Valtype*>(wv), v); } +}; + +// We need to specialize the 8-bit version of Swap to avoid +// conflicting overloads, since both versions of readval and writeval +// will have the same type parameters. + +template<bool big_endian> +struct Swap<8, big_endian> +{ + typedef typename Valtype_base<8>::Valtype Valtype; + + static inline Valtype + readval(const Valtype* wv) + { return *wv; } + + static inline void + writeval(Valtype* wv, Valtype v) + { *wv = v; } +}; + +// Swap_unaligned is a template based on size and on whether the +// target is big endian. It defines the type Valtype and the +// functions readval and writeval. The functions read and write +// values of the appropriate size out of buffers which may be +// misaligned. + +template<int size, bool big_endian> +struct Swap_unaligned; + +template<bool big_endian> +struct Swap_unaligned<8, big_endian> +{ + typedef typename Valtype_base<8>::Valtype Valtype; + + static inline Valtype + readval(const unsigned char* wv) + { return *wv; } + + static inline void + writeval(unsigned char* wv, Valtype v) + { *wv = v; } +}; + +template<> +struct Swap_unaligned<16, false> +{ + typedef Valtype_base<16>::Valtype Valtype; + + static inline Valtype + readval(const unsigned char* wv) + { + return (wv[1] << 8) | wv[0]; + } + + static inline void + writeval(unsigned char* wv, Valtype v) + { + wv[1] = v >> 8; + wv[0] = v; + } +}; + +template<> +struct Swap_unaligned<16, true> +{ + typedef Valtype_base<16>::Valtype Valtype; + + static inline Valtype + readval(const unsigned char* wv) + { + return (wv[0] << 8) | wv[1]; + } + + static inline void + writeval(unsigned char* wv, Valtype v) + { + wv[0] = v >> 8; + wv[1] = v; + } +}; + +template<> +struct Swap_unaligned<32, false> +{ + typedef Valtype_base<32>::Valtype Valtype; + + static inline Valtype + readval(const unsigned char* wv) + { + return (wv[3] << 24) | (wv[2] << 16) | (wv[1] << 8) | wv[0]; + } + + static inline void + writeval(unsigned char* wv, Valtype v) + { + wv[3] = v >> 24; + wv[2] = v >> 16; + wv[1] = v >> 8; + wv[0] = v; + } +}; + +template<> +struct Swap_unaligned<32, true> +{ + typedef Valtype_base<32>::Valtype Valtype; + + static inline Valtype + readval(const unsigned char* wv) + { + return (wv[0] << 24) | (wv[1] << 16) | (wv[2] << 8) | wv[3]; + } + + static inline void + writeval(unsigned char* wv, Valtype v) + { + wv[0] = v >> 24; + wv[1] = v >> 16; + wv[2] = v >> 8; + wv[3] = v; + } +}; + +template<> +struct Swap_unaligned<64, false> +{ + typedef Valtype_base<64>::Valtype Valtype; + + static inline Valtype + readval(const unsigned char* wv) + { + return ((static_cast<Valtype>(wv[7]) << 56) + | (static_cast<Valtype>(wv[6]) << 48) + | (static_cast<Valtype>(wv[5]) << 40) + | (static_cast<Valtype>(wv[4]) << 32) + | (static_cast<Valtype>(wv[3]) << 24) + | (static_cast<Valtype>(wv[2]) << 16) + | (static_cast<Valtype>(wv[1]) << 8) + | static_cast<Valtype>(wv[0])); + } + + static inline void + writeval(unsigned char* wv, Valtype v) + { + wv[7] = v >> 56; + wv[6] = v >> 48; + wv[5] = v >> 40; + wv[4] = v >> 32; + wv[3] = v >> 24; + wv[2] = v >> 16; + wv[1] = v >> 8; + wv[0] = v; + } +}; + +template<> +struct Swap_unaligned<64, true> +{ + typedef Valtype_base<64>::Valtype Valtype; + + static inline Valtype + readval(const unsigned char* wv) + { + return ((static_cast<Valtype>(wv[0]) << 56) + | (static_cast<Valtype>(wv[1]) << 48) + | (static_cast<Valtype>(wv[2]) << 40) + | (static_cast<Valtype>(wv[3]) << 32) + | (static_cast<Valtype>(wv[4]) << 24) + | (static_cast<Valtype>(wv[5]) << 16) + | (static_cast<Valtype>(wv[6]) << 8) + | static_cast<Valtype>(wv[7])); + } + + static inline void + writeval(unsigned char* wv, Valtype v) + { + wv[0] = v >> 56; + wv[1] = v >> 48; + wv[2] = v >> 40; + wv[3] = v >> 32; + wv[4] = v >> 24; + wv[5] = v >> 16; + wv[6] = v >> 8; + wv[7] = v; + } +}; + +// Swap_aligned32 is a template based on size and on whether the +// target is big endian. It defines the type Valtype and the +// functions readval and writeval. The functions read and write +// values of the appropriate size out of buffers which may not be +// 64-bit aligned, but are 32-bit aligned. + +template<int size, bool big_endian> +struct Swap_aligned32 +{ + typedef typename Valtype_base<size>::Valtype Valtype; + + static inline Valtype + readval(const unsigned char* wv) + { return Swap<size, big_endian>::readval( + reinterpret_cast<const Valtype*>(wv)); } + + static inline void + writeval(unsigned char* wv, Valtype v) + { Swap<size, big_endian>::writeval(reinterpret_cast<Valtype*>(wv), v); } +}; + +template<> +struct Swap_aligned32<64, true> +{ + typedef Valtype_base<64>::Valtype Valtype; + + static inline Valtype + readval(const unsigned char* wv) + { + return ((static_cast<Valtype>(Swap<32, true>::readval(wv)) << 32) + | static_cast<Valtype>(Swap<32, true>::readval(wv + 4))); + } + + static inline void + writeval(unsigned char* wv, Valtype v) + { + typedef Valtype_base<32>::Valtype Valtype32; + + Swap<32, true>::writeval(wv, static_cast<Valtype32>(v >> 32)); + Swap<32, true>::writeval(wv + 4, static_cast<Valtype32>(v)); + } +}; + +template<> +struct Swap_aligned32<64, false> +{ + typedef Valtype_base<64>::Valtype Valtype; + + static inline Valtype + readval(const unsigned char* wv) + { + return ((static_cast<Valtype>(Swap<32, false>::readval(wv + 4)) << 32) + | static_cast<Valtype>(Swap<32, false>::readval(wv))); + } + + static inline void + writeval(unsigned char* wv, Valtype v) + { + typedef Valtype_base<32>::Valtype Valtype32; + + Swap<32, false>::writeval(wv + 4, static_cast<Valtype32>(v >> 32)); + Swap<32, false>::writeval(wv, static_cast<Valtype32>(v)); + } +}; + +} // End namespace elfcpp. + +#endif // !defined(ELFCPP_SWAP_H) |